Suunto D9 manual Battery power indication, Low battery warning is indicated by the battery symbol

5.10.3. Battery power indication

Temperature or internal oxidation of the battery affect the battery voltage. If the instrument is stored for a long period, or used in cold temperatures, the low battery warning may be displayed even though the battery has enough capacity. In these cases, re-enter DIVE mode to receive the battery power indication.

After the battery check, the Low Battery Warning is indicated by the battery symbol.

If the battery symbol is displayed in the Surface mode, or if the display is faded or weak, the battery may be too low to operate the dive computer, and battery replacement is recommended.

NOTE	For safety reasons, the backlight cannot be activated when the
	low battery warning is indicated by the battery symbol.

The optional wireless pressure transmitter sends out a lowbat (LOBT) warning when its battery voltage is getting low. This is shown intermittently instead of the pressure reading (see Section 5.3). When you get this warning, the pressure transmitter's battery needs to be replaced.

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